Method and apparatus for removing snow from a roof

ABSTRACT

A snow removal knife includes a knife assembly operably, disengagably connectable to a handle assembly and having a pole interface disposed on a knife assembly upper margin, the knife assembly presenting a substantially planar knife assembly lower margin and having a distal cutting edge, the cutting edge being non-coplanar with the knife assembly lower margin, the cutting edge being upwardly directed relative to the knife assembly lower margin to define a roof engaging surface proximate an intersection of the knife assembly lower margin and the distal cutting edge. A method of forming the knife is further included.

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of removal of snow accumulation from a roof structure. More specifically, the present invention relates to a method and apparatus allowing for the safe and convenient removal of accumulated snow from a roof structure utilizing a lightweight snow removal knife.

BACKGROUND OF THE INVENTION

[0002] In climates that experience winter conditions, it is common for snow to accumulate on roof structures. As this snow accumulates through either continued snowfall or through the action of wind, this snow accumulation can lead to a variety of problems to the structure. These problems can include possible damage to the structure as well as creating safety concerns for individuals who are using the structure.

[0003] As the accumulated snow compresses and hardens, ice can form at the interface between the roof and the snow. This ice can result in ice dams, which prevents the roof from shedding moisture properly. The creation of ice dams ultimately leads to roof leakage and possible interior damage to the structure. Once the ice dam is formed, removal of the ice dam is typically accomplished through the physical labor of the structure owner. Removal of the ice dam necessarily puts the structure owner in an unsafe environment and typical removal methods can lead to further roof damage.

[0004] Individuals can also be put into harms way when accumulated snow melts off the roof structure through heat radiated through the roof or because of warmer weather conditions or direct sunlight. As the snow melts, the water can drip off of the roof creating slippery conditions on any walkways surrounding the edge of the structure. Melting snow can also lead to the creation of icicles on roof overhangs. These icicles can lead to direct physical injury by falling on a passerby. Finally, as accumulated snow melts, large patches of snow can become dislodged and slide off the roof leading to inconvenience and possible injury to passersby.

[0005] Because of the possible inconvenience and harm that accumulated snow can present on a roof structure, a variety of methods and tools have been developed to remove these accumulations.

[0006] U.S. Pat. No. 3,091,790 discloses a snow removal device utilizing a multi-edged blade connected to an elongated handle. The blade is oriented so that in use, it is perpendicular to the roof surface. The user lifts the blade to as high a position on the roof as he can reach and proceeds to drag the snow down in his direction. The blade includes one edge with a flexible flapper to be used with fresh, loose snow. The blade also includes a toothed edge for use in removing built up ice.

[0007] U.S. Pat. No. 3,483,643 discloses a snow removal device utilizing a pivoting blade assembly connected to a sectional handle. The device is designed so that the blade slides over the top of the accumulated snow as the user pushes the device to the peak of the roof. The user then pulls the device in a downward direction causing the blade to rotate and drag the accumulated snow downward toward the user.

[0008] U.S. Pat. No. 3,773,375 discloses a snow removal device utilizing a blade connected to a sectional handle. The blade is oriented so that it is perpendicular to the plain of the roof. The blade is lifted above the snow surface and placed as high on the roof as the user can reach. The user then pulls the blade toward himself causing the snow to slide in his direction.

[0009] U.S. Pat. No. 3,998,486 discloses a snow removal device utilizing a flexible, low-friction sheet. The sheet is attached to a rod having wheels at its ends. The rod being connected to a frame which is ultimately connected to a sectional handle. The device is placed at the edge of the roof and the user pushes the device up the roof and through the snow. The rod is designed to undercut the snow that then slides down the low-friction sheet in the direction of the user.

[0010] U.S. Pat. No. 4,024,654 discloses a snow removal device using a blade with two pulling devices. The first pulling device is used to pull the blade to the top of the roof by pulling from the opposite side in which you intend to remove the snow. When the blade reaches the top of the roof, the user moves to the side of the structure in which it is desired to remove the snow. The user pulls on the second pulling device to drag the blade through the snow. This results in the snow being slidably removed in the direction of the user.

[0011] U.S. Pat. No. 4,089,127 discloses a snow removal device utilizing a chute attached to an elongated handle. The device is placed on the edge of the roof and the user applies a bias to the handle resulting in the chute moving up and through the snow accumulation. The dislodged snow slides down the chute in the direction of the user.

[0012] U.S. Pat. No. 6,092,315 discloses a snow removal device having a wheeled frame and slide attached to an elongated handle. The wheeled frame is placed at the edge of the roof and the user biases the wheeled frame to the peak of the roof. The frame cuts through the accumulated snow causing it to slide down the chute in the direction of the user.

[0013] A wide variety of prior art concerned with various snow shovel and scoop designs exists including U.S. Pat. No. 195,198 disclosing a method to increase the strength and efficiency of snow shovels, U.S. Pat. No. 941,271 disclosing a strong but inexpensive snow shovel design, and U.S. Pat. No. 2,752,631 disclosing a combination shovel and snow mold assembly.

[0014] Each of the aforementioned systems for snow removal from roofs suffers from disadvantage. Use of some of these designs can lead to shingle and roof structure damage. Nearly all of the designs call for the snow to be removed through a sliding action in the direction of the user. These designs are also unwieldy leading to difficulties in lifting, manipulating and operating the devices. What is needed is a device that overcomes the limitations of the prior art.

SUMMARY OF THE INVENTION

[0015] The snow removal device of the present invention overcomes the limitations of the aforementioned devices by providing a lightweight device that can be directed to undercut the snow pack disposed on the roof without disadvantageously engaging roof shingles.

[0016] The present invention is a snow removal knife including a knife assembly operably, disengagably connectable to a handle assembly and having a pole interface disposed on a knife assembly upper margin, the knife assembly presenting a substantially planar knife assembly lower margin and having a distal cutting edge, the cutting edge being non-coplanar with the knife assembly lower margin, the cutting edge being upwardly directed relative to the knife assembly lower margin to define a roof engaging surface proximate an intersection of the knife assembly lower margin and the distal cutting edge. The present invention further includes a method of forming the snow removal knife.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a perspective view of the snow removal knife of the present invention;

[0018]FIG. 1a is a sectional view of the distal edge of the snow removal knife taken through the snow removal knife center axis;

[0019]FIG. 2 is a top view of the knife assembly;

[0020]FIG. 3 is a side view of the distal edge of the knife assembly;

[0021]FIG. 4 is an enlarged side view of the distal edge of the knife assembly;

[0022]FIG. 5 is a schematic drawing of a structure having a snow-covered roof;

[0023]FIG. 6 is a schematic drawing of the structure in which a user has begun using the snow removal device;

[0024]FIG. 7 is a schematic drawing of the structure in which the user has cleared less than half of the roof with the snow removal device;

[0025]FIG. 8 is a schematic drawing of the structure in which the user has cleared more than half of the roof with the snow removal device; and

[0026]FIG. 9 is a schematic drawing of the structure in which the user has cleared the roof with the snow removal device;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A snow removal knife according to an embodiment of the present invention is illustrated at 100 in FIG. 1. The snow removal knife 100 of the present invention includes a lightweight elongated handle assembly 110, a gripping portion 120 and a knife assembly 130.

[0028] The handle assembly 110 preferably includes extension means allowing a user to increase the reach of the snow removal knife 100. The gripping portion 120 provides the user was a safe and sure grip of the snow removal knife 100. The knife assembly 130 is designed such that the snow removal knife 100 can exhibit a slicing action when moved in either a vertical or horizontal orientation.

[0029] The design of the present invention provides a number of user enhancements that are not exhibited by prior art snow removal devices. The lightweight design requires less strength on the part of the operator to lift and operate the device. The gripping portion 120, if constructed from an electrically insulating material, can provide a measure of safety to the user when power cables and wires are located in the vicinity of the roof structure. Finally, the ability to laterally slide the snow removal knife 100 allows a user to clear snow in a manner that prevents sliding snow from falling upon the user.

[0030] The handle assembly 110 is constructed of lightweight materials and includes a series of hollow, pole sections 140 adapted for quick interconnection with one another. One end of the pole section 140 is preferably designed with a protrusion 150 having an outside diameter that is slightly less than the inside diameter of an end of another pole section 140. When mated to the knife assembly 130, the handle assembly 110 is coincident with the center axis 112 of the snow removal knife 100.

[0031] The protrusion 150 preferably includes a spring loaded locking mechanism 160 that is compressed as the protrusion 150 is inserted into the pole section 140. On each pole section 140, the end opposite the protrusion 150 includes a small diameter bore 170 that is slightly larger than the spring loaded locking mechanism 160.

[0032] As the protrusion 150 is inserted into the hollow end of the second pole section 140, the spring loaded locking mechanism 160 is released into the small diameter bore 170 effectively the locking pole sections 140 together. This process can be repeated for any number of pole sections 140 depending upon the desired length of the snow removal knife 100.

[0033] The pole sections 140 can be separated by forcibly depressing the spring loaded locking mechanism 160 and sliding the protrusion 150 out of the hollow end of the pole section 140. The pole sections 140 may be manufactured of aluminum but a suitable electrically non-conductive material that is both lightweight and possessing sufficient strength and rigidity could be used. This may be a plastic, fiberglass, or other non-metallic material.

[0034] The gripping portion 120 consists of a tubular section that can optionally be of an electrically insulated material. A rubber handgrip 180 is placed over one end of the gripping portion 120. The other end includes a protrusion 150 with spring loaded locking mechanism 160. The protrusion 150 is inserted into the hollow end of the pole section 140. The spring loaded locking mechanism 160 on the gripping portion 120 interacts with a small diameter bore 170 on the pole section 140 effectively locking the two pieces together. The gripping portion 120 is preferably constructed of a lightweight metal such as aluminum, or can be made from fiberglass or any other suitable non-conducting material possessing sufficient strength and rigidity.

[0035] The knife assembly 130, which is illustrated in FIGS. 1-5, preferably comprises a precision-machined laminate sheet 190. The laminate sheet 190 is generally planar and has four edges, comprising a distal edge 200 furthest from the gripping portion 120, a proximal edge 210 nearest the gripping portion 120, and two spaced apart generally parallel side edges 220. The distal edge 200 may be gently curved, bending back toward the points of intersection with the two spaced apart generally parallel side edges 220. The laminate sheet 190 has an upper margin 222 and an opposed lower margin 227. The lower margin 227 is generally planar so that the lower margin presents no raised surfaces to disadvantageously engage the shingles of the roof.

[0036] Referring to FIGS. 1 and 1a, the distal edge 200, the proximate edge 210, and the side edges 220 each contain a cutting edge 225. The cutting edge 225 of the distal edge 200 comes to a radiused tip 226. The cutting edge 225 is directed upward to define a beveled surface 228 so that the actual tip 226 is elevated relative to the bottom margin 227 when the bottom margin 227 is in a generally horizontal disposition. By elevating the tip 226, a roof engaging surface 223 is defined proximate the intersection of the beveled surface 228 and the lower margin 227, the actual location of the engaging surface 223 being a function of the angle of the lower margin 227 with the plane of the roof. The elevated tip 226 thereby slides over roofing shingles without catching and causing any damage to either the knife assembly 130 or the roof.

[0037] A plurality of spaced apart, generally parallel strengthening strakes 229 extend rearward from the tip 226 on the upper margin 222. The strakes 229 are tapered and gradually blend into the upper margin 222.

[0038] The laminate sheet 190 is designed so that the cross-section of the laminate sheet 190 tapers from a maximum sheet thickness at the proximate edge 210 to a minimum sheet thickness at the distal edge 200. The tapered edge design provides for a minimum cross-section at the cutting edge 225 on the distal edge 200 and a maximum cross-section at the cutting edge 225 at the sweeping interface of the proximate edge 210.

[0039] The laminate sheet 190 preferably includes a molded pole interface 230 disposed on the upper margin 222 so as to leave the lower margin 227 planar. The pole interface 230 has small a diameter bore 240 sized to interface with the spring loaded locking mechanism 160 found on the protrusion 150 of the pole section 140. The knife assembly 130 is both bendable and resilient, such that it resumes its original shape after being deflected from the original shape.

[0040] The knife assembly 130 is preferably constructed of a high density polyethylene material or a high density polycarbonate material such as Lexan plastic, but any suitable high-impact plastic possessing qualities including lightweight, strength, and resilience could be used.

[0041] The use of the snow removal knife 100 is depicted in FIGS. 5-9. During use of the snow removal knife 100, a user 240 assembles the snow removal knife 100 to the proper length by attaching the gripping portion 120 and the knife assembly 130 to the desired number of pole sections 140 via the spring loaded locking mechanisms 160.

[0042] The user 240 then lifts the knife assembly 130 to the base of structure roof 250 that is covered in snow 260. The user 240 proceeds to push the knife assembly 130 up the structure roof 250, such that the knife assembly 130 is generally parallel to the roof surface and is riding just above the roof surface and under cutting the bulk of the snow pack on the roof.

[0043] The knife assembly 130 may also be employed in a generally orthogonal disposition relative to the roof surface to make generally parallel cuts through the depth dimension of the snow pack on the roof. By doing this before undercutting the snow pack as noted above, the undercutting action then results in discrete blocks of the snow pack being dislodged, a pair of generally parallel, spaced apart, depth cuts defining the edges of the discrete block.

[0044] The distal edge 200 of the knife assembly 130 slices any bond between the snow 260 and the structure roof 250. When the bond is broken, the snow 260 slides off the structure roof 250 by means of gravity. The user 240 can also rotate the gripping portion 120 in a lateral motion. This allows the high impact knife assembly 130 to travel sideways across the structure roof 250 while the user 240 maintains a stationary position. In this manner, the user 240 can cause the snow 260 to be removed from the structure roof 250 with no danger of the snow 260 falling upon the user 240.

[0045] Through the use of the spring loaded locking mechanism 160, the present invention can be disassembled into individual pieces for storage when not in use. The modular design also allows for quick, easy and inexpensive replacement of any components that have worn or broken during use.

[0046] It is contemplated that features disclosed in this application, as well as those described in the above applications incorporated by reference, can be mixed and matched to suit particular circumstances. Various other modifications and changes will be apparent to those of ordinary skill. 

1. A snow removal knife for removing snow from a roof surface comprising: a knife assembly having a top margin and a substantially planar lower margin and a plurality of edges including a distal edge, wherein the distal edge is formed with a cutting edge and roof contact edge, wherein the cutting edge is not co-planar with the roof contact edge such that the cutting edge does not contact the roof surface when the roof contact edge is in contact with the roof surface, and a pole interface formed on the top margin proximate the proximate edge; a handle assembly having a plurality of pole sections, wherein each pole section has an interior diameter and includes a terminal end, wherein the terminal end includes structure defining a protrusion with an outer diameter, wherein the outer diameter is less than the interior diameter of the pole section, wherein each pole section has interconnection means, whereby a plurality of pole sections may be interconnected together to increase the overall length of the handle assembly and whereby a connection may be maintained with the pole interface; and a gripping portion including a proximate end and a distal end, wherein the proximate end includes a handgrip, wherein the distal end includes interconnection means, whereby the gripping portion may be connected to the handle assembly.
 2. The snow removal knife of claim 1, wherein a cross sectional of the knife assembly taken along a center axis tapers from a maximum value at the proximate edge to a minimum value at the distal edge.
 3. The snow removal knife of claim 1, wherein the interconnection means comprises a spring loaded locking mechanism.
 4. The snow removal knife of claim 1, wherein the pole interface further includes a spring loaded locking mechanism.
 5. The snow removal knife of claim 1, wherein the gripping portion is constructed of an electrically insulated material.
 6. The snow removal knife of claim 1, wherein the knife assembly is constructed of a high-density polyethylene material.
 7. The snow removal knife of claim 1, wherein the knife assembly is constructed of a high impact plastic material.
 8. A method of forming a snow removal knife comprising: assembling a plurality of pole sections, forming each pole section hollow and with an interior diameter and including a terminal end, said terminal end including structure defining a protrusion with an outer diameter, said outer diameter less than said interior diameter of the pole section; connecting a gripping portion to the handle assembly; connecting a knife assembly to the handle assembly, forming said knife assembly including an upper and a substantially planar lower surface and including a proximate edge and a distal edge, forming said distal edge with a cutting edge and roof contact edge, forming said cutting edge non-coplanar with the roof contact edge.
 9. A snow removal knife comprising: a knife assembly operably, disengagably connectable to a handle assembly and having a pole interface disposed on a knife assembly upper margin, the knife assembly presenting a substantially planar knife assembly lower margin and having a distal cutting edge, the cutting edge being non-coplanar with the knife assembly lower margin, the cutting edge being upwardly directed relative to the knife assembly lower margin to define a roof engaging surface proximate an intersection of the knife assembly lower margin and the distal cutting edge.
 10. The snow removal knife of claim 9 including the cutting edge being beveled relative to the knife assembly lower margin.
 11. The snow removal knife of claim 9 including the knife assembly being formed of a resilient material and having strengthening structure.
 12. The snow removal knife of claim 11 including the strengthening structure comprising a plurality of strakes disposed on the knife assembly upper margin proximate the cutting edge.
 13. The snow removal knife of claim 11 including the strengthening structure comprising forming the knife assembly with a tapered cross section, a cross sectional dimension being greatest proximate the proximal edge.
 14. The snow removal knife of claim 9, the handle assembly including at least one pole, the pole having a spring loaded locking mechanism for disengagable mating with the knife assembly pole interface.
 15. The snow removal knife of claim 14 including the locking mechanism being engagable with a detent formed in the knife assembly pole interface.
 16. The snow removal knife of claim 9, the handle assembly including a plurality of poles, each pole having a spring loaded locking mechanism for disengagable mating with the knife assembly pole interface or with another pole.
 17. The snow removal knife of claim 14 including the locking mechanism being engagable with a detent formed in the knife assembly pole interface or formed in the other pole.
 18. The snow removal knife of claim 9, including the handle assembly being formed of an electrically non-conductive material.
 19. The snow removal knife of claim 9, a gripping portion including at least one pole, the pole having a spring loaded locking mechanism for disengagable mating with the knife assembly pole interface or with the handle assembly as desired.
 20. The snow removal knife of claim 19 including the locking mechanism being engagable with a detent formed in the knife assembly pole interface or formed in the handle assembly.
 21. The snow removal knife of claim 19, including the gripping portion being formed of an electrically non-conductive material.
 22. A method of forming a snow removal knife comprising: forming a knife assembly operably, disengagably connectable to a handle assembly; forming a pole interface disposed on a knife assembly upper margin; forming the knife assembly with a substantially planar knife assembly lower margin and with a distal cutting edge; forming the cutting edge non-coplanar with the knife assembly lower margin, the cutting edge being upwardly directed relative to the knife assembly lower margin; and defining a roof engaging surface proximate an intersection of the knife assembly lower margin and the distal cutting edge.
 23. The method of claim 22 including forming the cutting edge beveled relative to the knife assembly lower margin.
 24. The method of claim 22 including forming the knife assembly of a resilient material and including strengthening structure.
 25. The method of claim 24 including forming a plurality of strakes disposed on the knife assembly upper margin proximate the cutting edge to define the strengthening structure.
 26. The method of claim 24 including forming the knife assembly with a tapered cross section, a cross sectional dimension being greatest proximate the proximal edge to define the strengthening structure.
 27. The method of claim 22, including forming the handle assembly of at least one pole and including a spring loaded locking mechanism for disengagable mating with the knife assembly pole interface.
 28. The method of claim 27 including forming a detent in the knife assembly pole interface and forming the locking mechanism engagable with the detent.
 29. The method of claim 22, including forming the handle assembly of a plurality of poles and including with each pole a spring loaded locking mechanism for disengagable mating with the knife assembly pole interface or with another pole.
 30. The snow removal knife of claim 27 including forming a detent in the knife assembly pole interface and forming a detent formed in the other pole, and forming the locking mechanism being engagable with both detents.
 31. The method of claim 22, including forming the handle assembly of an electrically non-conductive material.
 32. The method of claim 9, including forming a gripping portion including at least one pole and forming a pole spring loaded locking mechanism for disengagable mating with the knife assembly pole interface or with the handle assembly as desired.
 33. The method of claim 32 including forming a detent in the knife assembly pole interface and forming a detent in the handle assembly, and forming the locking mechanism engagable with either detent.
 34. The snow removal knife of claim 32, including forming the gripping portion of an electrically non-conductive material. 